1. Field of the Invention
The present invention pertains to the field of computer aided design. More particularly, this invention relates to an enhanced chronological feature browser for computer aided design.
2. Background
As technology has advanced, computer systems have become more and more commonplace in a wide variety of home and business environments. One use of such computer systems is for computer aided design (CAD) applications which allow users to design various products in varying degrees of detail.
One type of CAD application is referred to as feature-based CAD or parametric CAD. In feature-based CAD, objects are created by identifying multiple features and defining relationships or dependencies among those features. A feature refers to one or more lines of an object. For example, one feature may identify a cube and a second feature may identify a hole, while a relationship between the features indicates where in the surface the hole occurs.
Feature-based CAD programs typically provide a "feature browser" display that identifies to the user the chronological and hierarchical dependencies among features. The chronological dependencies identify an ordering of the display of features of an object during the actual displaying of the object (e.g., the hole should be displayed after the surface in the above example to ensure that the surface doesn't cover the hole). The hierarchical dependencies identify which features are part of which other features (e.g., an object may include multiple surfaces and multiple holes, each of which are a part of the feature).
However, additional dependencies, referred to as "logical" dependencies, can also exist among features. As used herein, "logical" dependencies refer to non-chronological and non-hierarchical relationships between two or more features. Examples of logical dependencies include parameters which are shared among two or more features, and constraints which identify positional relationships between features (e.g., two lines are to be parallel, two features are to share an edge, etc.). However, typical prior art CAD applications do not provide a method for identifying logical dependencies which are easily readable by a user.
Thus, a need exists for an enhanced chronological feature browser for CAD systems.